21Shares Warns 24 of Top 26 Blockchains Still Lack Quantum-Resistant Defenses
Updated
Updated · 21shares.com · Jun 1
21Shares Warns 24 of Top 26 Blockchains Still Lack Quantum-Resistant Defenses
3 articles · Updated · 21shares.com · Jun 1
Summary
21Shares says quantum computing is not yet able to break Bitcoin, Ethereum or Solana, but allocators should prepare now because the response window is shrinking and a Bitcoin-wide migration alone could take five to seven years.
Google’s March 2026 research cut the estimated computing power needed to crack crypto protections by about 20 times, highlighting that algorithmic breakthroughs—not just hardware gains—can suddenly pull forward the threat timeline.
The report says the main danger is loss of ownership control rather than blockchain history, with risk concentrated in bridges, treasury accounts and operators; bridges have already lost nearly $3 billion since 2022 without any quantum attack.
One threat is already active: attackers can harvest exposed account data now and decrypt it later, while Google’s research also flagged a potential one-shot attack that could leave lasting weaknesses in parts of Ethereum’s infrastructure.
Governments and tech groups are moving faster than crypto networks—the US mandates quantum-resistant protection for new national security systems from January 2027, Google set a 2029 migration target, and 24 of the top 26 protocols still rely on aging cryptography.
Why are major blockchains lagging so far behind governments in the race to become quantum-resistant?
Could AI's help in quantum computing cause a crypto collapse before networks are able to react?
The 2026 Quantum Threat to Blockchain: Urgency, Economic Risks, and the Race for Post-Quantum Security
Overview
As of June 2026, the quantum computing threat to blockchain technology has become urgent, driven by new research from leading institutions and the emergence of Cryptographically Relevant Quantum Computers (CRQCs). These advanced machines can directly attack the cryptographic algorithms that secure blockchain transactions, especially those based on ECDLP-256, putting both the technical integrity and market stability of cryptocurrencies at risk. The security of blockchain systems is closely tied to public confidence, making the quantum threat a dual challenge: it threatens not only the technology itself but also the trust and value that support digital assets.